1. Field of the Invention
This invention relates to an image forming method and an image forming apparatus for forming images using a recording section for recording visible images and a nip region for effecting a flattening process after the visible images are formed.
2. Description of Related Art
A majority of known image forming methods form images by forming visual images using color materials such as dyes and pigments on a recording medium. Such methods, however, raise problems when the recording medium is to be preserved, in that the color materials may be discolored or faded due to operation of ozone or light or that bleeding or the like may occur due to contact with water. There is also a problem that glossing property of the visible image cannot be obtained adequately because the color materials form the surface layer. To treat with this problem, a method for flattening a sheet after recording is effective. Japanese Unexamined Patent Publication No. 4-21446 discloses an image forming apparatus of this kind. FIG. 4 shows a schematic structure of such an apparatus. In FIG. 4, numeral 1 is a fan for blowing warm air; numeral 2 is a heater for warm air; numeral 3 is a belt drive roller; numeral 4 is a fixing belt; numeral 5 is a press roller; numeral 6 is a separation roller; numeral 7 is a heater for pre-drying; numeral 8 is a heat-resistance film; numeral 9 is a fixing heater; numeral 10 is a cooling fan; numeral 11 is a roller; and numeral 13 is a conveyance roller. A recording medium is guided by the heater for pre-drying, and after melting by means of the press roller 5 and the fixing heater 9 with pressure and heat while sandwiched by the fixing belt 4 and the heat-resistance film 8, the recording medium is cooled down to obtain a stable transparent flattened layer.
Such a conventional apparatus has an advantage in that the transparent flattened layer can be obtained stably. The apparatus, however, raises problems where the recording medium with a flattening layer and an ink reception layer is processed with heat and pressure as a flattening process right after the inks create visual images, such that image density is lowered, that the flattening layer is deformed, and that peeling or swelling or cracking of films may occur, since the ink solvent remains in the flattening layer or between the flattening layer and the ink reception layer. Other approaches to cope with such a problem were mainly to arrange multiple dryers and a laminating means for processing the recording medium after images are formed thereon using color materials such as dyes and pigments in a manner as described in the above conventional art or to place a considerable length for conveyance before the recording medium enters such a laminating means. Such an apparatus, however, raises problems such as its structure becomes complicated, manufacturing costs are increased, and the size of the apparatus is enlarged. In any event, the main object of the invention is to process good images with high speed and to eliminate partial image defects that occur when the medium formed with images using inks including color materials and an ink solvent on a porous layer is heated and pressed, or namely, to eliminate partial "peeling" in the multilayer structure occurring due to the gaseous solvent.